Introduction:

The role of limited versus extended pelvic lymph node dissection (PLND) in the surgical management of PCa patients remains controversial. We sought to conduct a National Cancer Database (NCDB) analysis evaluating the impact of the extent of lymphadenectomy on survival outcomes for patients presenting with intermediate- and high-risk PCa. 

Methods:

The NCDB was queried to identify patients with intermediate and high-risk PCa who were treated by RP and PLND from 2004 to 2013 to allow for a minimum of 5-year survival analysis. Intermediate and high-risk patients were defined according to the AUA guidelines (Intermediate risk: cT2b-2c and/or PSA=10–20ng/ml and/or Grade Group 2 or 3; High-risk ≥cT3 and/or PSA>20ng/mL and/or Grade Group 4 or 5). We limited our cohort to men <70 years of age with a Charlson Comorbidity index=0.  

Patients were divided into 3 groups according to the number of excised lymph nodes as a surrogate for the extent of lymph node dissection (Group1:1–9, Group2:10–19, and Group3:≥20 nodes).  The primary outcome was overall survival (OS), all-cause mortality was evaluated using propensity score weighted Kaplan Meir Curves and Cox regression models.  The secondary outcome was the rate of lymph node-positive disease among different groups.  

Results:

A total of 103,250 patients had a new diagnosis of PCa and met the inclusion criteria. 74.2% of the patients had intermediate-risk, and 25.8% had high-risk PCa. The number of lymph nodes excised was <10 for 80.5%, 10-19 for 15.9%, and ≥20 for 3.6% of the patients. Figure 1 illustrates the Kaplan-Meir survival curves in the propensity score-weighted cohorts. In intermediate-risk PCa patients, propensity score-adjusted Cox regression analysis showed survival benefit for group 2 compared to group 1 (HR0.86, CI0.79-0.93, p<0.001).  Similarly, in high-risk PCa patients, group 3 had better survival likelihood compared to group 1 (HR0.61, CI0.47-0.78, p<0.001) (Table1).

Pathologically proven lymph node-positive disease rates were significantly higher in group 3 compared to group 1 and 2 in both intermediate and high-risk diseases. (Group 3 vs Group 1 and 2; intermediate risk 9.25% vs. 1.53% and 4.45%, p<0.001; high risk 25.25% vs. 5 .65%  and 15.53%,  p<0.001, respectively )

Conclusion:

Our results showed that for men with high-risk prostate cancer,  removal of 20  or more lymph nodes during radical prostatectomy  was associated with better survival outcomes. Similar survival benefit was noted in the intermediate-risk group with removal of 10-19 lymph nodes. Increased number of removed nodes was associated with increased likelihood of lymph node positivity and more accurate pathologic staging. 

Funding: N/A